Section design
Keep sections thin and open. The alloy works best where buckling or stiffness governs, such as stringers and beam caps.
Aluminium-lithium extrusions
2090-T86 Aluminium-Lithium Aerospace Extrusions
2090-T86 extrusions are aluminium-lithium bars, rods and profiles made for stiffeners, stringers and floor structure where every gram counts. Covered by AMS 4232, they are about 8 % lighter and 10 % stiffer than equivalent 7075 sections. Metline sources 2090 extrusions to order for aerospace and defence buyers worldwide, with full certification to the AMS revision on your drawing.
- Alloy
- 2090 (Al-Cu-Li-Zr)
- Temper
- T86
- Specification
- AMS 4232
- Density
- 2.59 g/cm³
What are 2090-T86 extrusions?
AMS 4232 covers 2090 extruded bars, rods and profiles in the T86 temper: solution heat-treated, cold worked by stretching about 6 % and artificially aged. The specification is limited to thin sections, up to about 12.7 mm (0.499 in) in diameter or least thickness and under 65 cm² in cross-section.
That scope reflects how the alloy is used. Al-Li extrusions replace 7075 or 2024 in thin stiffening members such as stringers, floor beam caps and frame sections, where higher modulus increases buckling resistance and lower density cuts weight. Thick Al-Li sections suffer from poor short-transverse properties, so heavy fittings are normally machined from other alloys.
The heavy stretch in T86 is not just for straightness. Cold work introduces dislocations on which the T1 (Al2CuLi) phase precipitates during ageing; without it, 2090 does not reach full strength. Re-heat-treating 2090 extrusions without restretching therefore gives lower properties.
2090 chemical composition (wt %)
| Element | Minimum | Maximum | Role |
|---|---|---|---|
| Copper (Cu) | 2.4 | 3.0 | Forms T1 (Al2CuLi) and θ′ strengthening phases |
| Lithium (Li) | 1.9 | 2.6 | Lowers density and raises stiffness; forms δ′ (Al3Li) |
| Zirconium (Zr) | 0.08 | 0.15 | Suppresses recrystallisation, keeps a fine grain structure |
| Magnesium (Mg) | — | 0.25 | Impurity / minor |
| Silicon (Si) | — | 0.10 | Impurity |
| Iron (Fe) | — | 0.12 | Impurity; kept low for toughness |
| Zinc (Zn) | — | 0.10 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Manganese, Chromium (each) | — | 0.05 | Impurities |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 93.2 – 95.6 % |
Mechanical and physical properties
2090-T86 extrusions reach high strength comparable to 7075-T6511 extrusions in thin sections, with published typical values in the region of 500 – 550 MPa tensile and 450 – 520 MPa yield and modest elongation. Exact minimum values by thickness and direction are given in AMS 4232 and on the mill certificate; we do not quote design values outside that document.
| Property | 2090-T86 extrusion | 7075-T6511 extrusion | 2024-T3511 extrusion |
|---|---|---|---|
| Density | 2.59 g/cm³ | 2.81 g/cm³ | 2.78 g/cm³ |
| Modulus | about 76 GPa | about 72 GPa | about 73 GPa |
| Specific stiffness (relative) | about 1.13 | 1.00 | about 1.03 |
| Strength level | High | High | Medium–high |
| Fatigue crack growth | Good | Fair | Very good |
Physical properties of 2090
- Density
- 2.59 g/cm³ (about 8 % lower than 7075)
- Modulus of elasticity
- About 76 GPa (roughly 10 % higher than 7075)
- Thermal conductivity
- About 88 W/m·K
- Thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- About 560 – 650 °C
Design and fabrication guidance
Directional properties
Check transverse and short-transverse properties in flanges and at fastener holes.
Forming
Limited formability in T86. Joggles and bends are best planned before final temper, or kept gentle.
Joining
Riveted and bonded assemblies are normal. Use sealant and wet-installed fasteners, as with other 2xxx alloys.
Corrosion protection
Anodise or conversion coat and prime. Al-Li alloys resist exfoliation well in T8 tempers but still need a protection scheme.
Scrap handling
Collect lithium-bearing chips and offcuts separately for recycling.
Supply and inspection
Supply details
- Forms
- Bars, rods and open profiles within AMS 4232 limits
- Section limits
- Up to about 12.7 mm least thickness; under 65 cm² cross-section
- Length
- Mill lengths or cut lengths to order
- Tolerances
- Per the AMS document and ANSI H35.2, or tighter by agreement
- Inspection
- Tensile tests, conductivity, dimensional, straightness and twist checks
- Certification
- EN 10204 3.1 certificate including lithium content and mechanical results
2090 extrusions are produced to order in campaigns. Existing dies for your section shorten the route considerably.
Typical uses
- Fuselage and wing stringers in weight-critical designs
- Floor beam caps and seat-track supports
- Frame and bulkhead stiffeners
- Missile and space vehicle longerons
A typical substitution replaces a 7075-T6511 stiffener with a 2090-T86 section of the same shape: weight falls by about 8 %, and the higher modulus improves buckling margin, provided the fatigue and transverse property checks are satisfied.
How to order 2090 extrusions
- SpecifySection drawing or die reference, temper (T86), length, quantity, AMS 4232 revision and any customer specification.
- Confirm the specificationWe check the order against the governing AMS, ASTM or EN document, confirm tempers, sizes, tolerances and any customer flow-down clauses, and quote on EXW, FOB, CIF or DAP terms.
- ProcessExtrusions are stretched, aged, cut, inspected and packed with lithium-bearing material clearly identified.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing heat or lot number, chemical analysis and mechanical test results, plus any ultrasonic or other inspection reports called for on the order.
- Pack and shipMaterial is protected against moisture and handling damage, packed in seaworthy cases or on pallets, marked for traceability and shipped by sea or air.
References and standards
- SAE AMS 4232 – Aluminum Alloy Extrusions 2.7Cu-2.2Li-0.12Zr (2090-T86)
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook Vol. 2 – Aluminum-Lithium Alloys
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products
2090 aluminium-lithium (aluminum-lithium) extrusions: FAQ
Which specification covers 2090-T86 extrusions?
SAE AMS 4232, which covers extruded bars, rods and profiles up to about 12.7 mm least thickness and under 65 cm² cross-section.
What is the density of 2090?
About 2.59 g/cm³, roughly 8 % below 7075 and 7 % below 2024.
Why is 2090 limited to thin extrusions?
Thick Al-Li sections have low short-transverse ductility and toughness, and the T86 temper depends on a heavy stretch that is easier to apply uniformly to thin sections.
Can 2090 extrusions be re-heat-treated?
Re-solution treating removes the cold work that T86 relies on. Without restretching, properties will be lower, so avoid re-heat-treatment unless the process is qualified.
Do you hold 2090 extrusions in stock?
No. 2090 sections are made to order in mill campaigns; send your requirement early so timing can be planned.
Need 2090-T86 extrusions?
Send your section, quantity and AMS revision, and we will confirm the route and certification.
